Exposure apparatus and method for manufacturing device

ABSTRACT

An exposure apparatus which exposes a substrate by projecting an image of a pattern, via an projection optical system and a liquid of a liquid immersion area formed on the substrate, onto the substrate, includes a liquid supply mechanism having supply ports for supplying the liquid on both sides of a projection area respectively and capable of simultaneously supplying the liquid from the supply ports, the image of the pattern being projected onto the projection area. The liquid supply mechanism supplies the liquid from only one of the supply ports disposed on the both sides when the mechanism starts to supply the liquid. The liquid may be supplied while moving an object such as a substrate placed to face the projection optical system. Accordingly, an optical path space on the image side of the projection optical system can be filled with the liquid quickly while suppressing formation of air bubbles.

CROSS-REFERENCE

This is a Division of application Ser. No. 11/325,654 filed Jan. 5,2006, which in turn is a Continuation Application of InternationalApplication No. PCT/JP2004/009999 which was filed on Jul. 7, 2004claiming the conventional priority of Japanese patent Application No.2003-272616 filed on Jul. 9, 2003. The disclosure of the priorapplications is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exposure apparatus and a method forproducing a device in which a substrate is exposed with a pattern insuch a state that a liquid immersion area is formed between a projectionoptical system and the substrate.

2. Description of the Related Art

Semiconductor devices and liquid crystal display devices are produced bymeans of the so-called photolithography technique in which a patternformed on a mask is transferred onto a photosensitive substrate. Theexposure apparatus, which is used in the photolithography step, includesa mask stage for supporting the mask and a substrate stage forsupporting the substrate. The pattern on the mask is transferred ontothe substrate via a projection optical system while successively movingthe mask stage and the substrate stage. In recent years, it is demandedto realize the higher resolution of the projection optical system inorder to respond to the further advance of the higher integration of thedevice pattern. As the exposure wavelength to be used is shorter, theresolution of the projection optical system becomes higher. As thenumerical aperture of the projection optical system is larger, theresolution of the projection optical system becomes higher. Therefore,the exposure wavelength, which is used for the exposure apparatus, isshortened year by year, and the numerical aperture of the projectionoptical system is increased as well. The exposure wavelength, which isdominantly used at present, is 248 nm of the KrF excimer laser. However,the exposure wavelength of 193 nm of the ArF excimer laser, which isshorter than the above, is also practically used in some situations.When the exposure is performed, the depth of focus (DOF) is alsoimportant in the same manner as the resolution. The resolution R and thedepth of focus δ are represented by the following expressionsrespectively.R=k ₁ λ/NA   (1)δ=±k ₂ ·λ/NA ²   (2)

In the expressions, λ represents the exposure wavelength, NA representsthe numerical aperture of the projection optical system, and k₁ and k₂represent the process coefficients. According to the expressions (1) and(2), the following fact is appreciated. That is, when the exposurewavelength λ is shortened and the numerical aperture NA is increased inorder to enhance the resolution R, then the depth of focus δ isnarrowed.

If the depth of focus δ is too narrowed, it is difficult to match thesubstrate surface with respect to the image plane of the projectionoptical system. It is feared that the focus margin is insufficientduring the exposure operation. Accordingly, the liquid immersion methodhas been suggested, which is disclosed, for example, in InternationalPublication No. 99/49504 as a method for substantially shortening theexposure wavelength and widening the depth of focus. In this liquidimmersion method, the space between the lower surface of the projectionoptical system and the substrate surface is filled with a liquid such aswater or any organic solvent to form a liquid immersion area so that theresolution is improved and the depth of focus is magnified about n timesby utilizing the fact that the wavelength of the exposure light beam inthe liquid is 1/n as compared with that in the air (n represents therefractive index of the liquid, which is about 1.2 to 1.6 in ordinarycases).

For example, when the liquid immersion area is formed on the substrateplaced on the substrate stage after the substrate is loaded on thesubstrate stage, it is required that the space between the substrate andthe projection optical system should be filled with the liquid in ashort period of time in view of the improvement in the throughput. Ifany bubble or the like is present in the liquid, the image of thepattern to be formed on the substrate is consequently deteriorated.Therefore, it is required that the liquid immersion area should beformed in a state in which no bubble is present.

SUMMARY OF THE INVENTION

The present invention has been made taking the foregoing circumstancesinto consideration, an object of which is to provide an exposureapparatus and a method for producing a device, in which the spacebetween a projection optical system and a substrate can be quicklyfilled with a liquid while suppressing the formation of any bubble orthe like, and the exposure process can be performed at a high throughputwithout causing any deterioration of an image of a pattern.

In order to achieve the object as described above, the present inventionadopts the following constructions corresponding to FIGS. 1 to 8 asillustrated in embodiments. However, parenthesized reference numeralsaffixed to respective elements merely exemplify the elements by way ofexample, with which it is not intended to limit the respective elements.

According to a first aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by projectingan image of a pattern through a liquid (1) onto the substrate, theexposure apparatus comprising:

a projection optical system (PL) which projects the image of the patternonto the substrate (P); and

a liquid supply mechanism (10) which has supply ports (13A, 14A) forsupply of the liquid (1) on both sides of a projection area (AR1)respectively and which supplies the liquid from the supply ports (13A,14A), the image of the pattern being projected onto the projection area(AR1) by the projection optical system (PL), wherein:

the liquid supply mechanism (10) supplies the liquid from only one ofthe supply ports (13A, 14A) disposed on the both sides when the liquidsupply mechanism (10) starts the supply of the liquid (1).

According to a second aspect of the present invention, there is providedan exposure method for exposing a substrate (P) by projecting an imageof a pattern through a liquid (1) onto the substrate (P), the exposuremethod comprising:

starting supply of the liquid (1) from one side of a projection area(AR1) to the projection area onto which the image of the pattern is tobe projected, before performing exposure operation;

supplying the liquid from both sides of the projection area (AR1) duringthe exposure operation; and

exposing the substrate by projecting the image of the pattern onto thesubstrate (P) through the supplied liquid.

According to the first and second aspects of the present invention, thesupply of the liquid is started from only one supply port of the supplyports arranged on the both sides of the projection area to form theliquid immersion area. Accordingly, it is possible to quickly form theliquid immersion area while suppressing the formation of any bubble orthe like. The mutual collision or the interference of the liquid, whichflows in the opposite directions, hardly occurs as compared with a casein which the supply of the liquid is started simultaneously from thesupply ports disposed on the both sides of the projection area.Therefore, the remaining of the bubble in the liquid immersion area issuppressed. Further, the liquid immersion area can be filled with theliquid more quickly and reliably. As a result, it is unnecessary toperform any process for removing the bubble or the like. Further, it ispossible to improve the throughput by shortening the period of timerequired for the liquid immersion area between the projection opticalsystem and the substrate to be filled with the liquid.

According to a third aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by projectingan image of a pattern through a liquid (1) onto the substrate, theexposure apparatus comprising:

a projection optical system (PL) which projects the image of the patternonto the substrate (P);

a liquid supply mechanism (10) which has supply ports (13A, 14A) forsupply of the liquid (1); and

a substrate-moving unit (PST) which moves the substrate (P), wherein:

the supply of the liquid (1) by the liquid supply mechanism (10) isstarted while moving the substrate (P) by the substrate-moving unit(PST).

According to a fourth aspect of the present invention, there is providedan exposure method for exposing a substrate (P) by projecting an imageof a pattern through a liquid (1) onto the substrate, the exposuremethod comprising:

starting supply of the liquid to a projection area (AR1) onto which theimage of the pattern is to be projected while moving the substrate (P)before performing exposure operation; and

exposing the substrate by projecting the image of the pattern onto thesubstrate (P) through the supplied liquid.

According to the third and fourth aspects of the present invention, thesupply of the liquid is started from the supply ports of the liquidsupply mechanism while moving the substrate to form the liquid immersionarea. Accordingly, it is possible to quickly form the liquid immersionarea while suppressing the formation of any bubble or the like. Inparticular, the period of time, which is required to sufficiently fillthe space between the projection optical system and the substrate withthe liquid, can be shortened, and the throughput can be improved ascompared with a case in which the liquid is supplied in a state in whichthe substrate is allowed to stand still when the liquid immersion areais formed. Further, the space between the projection optical system andthe substrate can be filled with the liquid more reliably.

According to a fifth aspect of the present invention, there is providedan exposure apparatus which exposes a substrate (P) by projecting animage of a pattern through a liquid (1) onto the substrate, the exposureapparatus comprising:

a projection optical system (PL) which projects the image of the patternonto the substrate (P); and

a liquid supply mechanism (10) which has supply ports (13A, 14A) forsupply of the liquid (1) on both sides of a projection area (AR1)respectively and which supplies the liquid from the supply ports (13A,14A), the image of the pattern being projected onto the projection area(AR1) by the projection optical system (PL), wherein:

the liquid supply mechanism (10) supplies the liquid in differentamounts respectively from the supply ports (13A, 14A) disposed on theboth sides when the liquid supply mechanism (10) starts the supply ofthe liquid (1).

According to a sixth aspect of the present invention, there is providedan exposure method for exposing a substrate (P) by projecting an imageof a pattern through a liquid (1) onto the substrate, the exposuremethod comprising:

starting supply of the liquid in different amounts respectively fromboth sides of a projection area onto which the image of the pattern isto be projected, before performing exposure operation; and

exposing the substrate by projecting the image of the pattern onto thesubstrate through the supplied liquid.

According to the fifth and sixth aspects of the present invention, theperiod of time, which is required to sufficiently fill the space betweenthe projection optical system and the substrate with the liquid, can beshortened, and the throughput can be improved. Further, the spacebetween the projection optical system and the substrate can be filledwith the liquid more reliably while suppressing the remaining of thebubble.

According to a seventh aspect of the present invention, there isprovided an exposure apparatus which exposes a substrate (P) byprojecting an image of a pattern through a liquid (1) onto thesubstrate, the exposure apparatus comprising:

a projection optical system (PL) which projects the image of the patternonto the substrate (P); and

a liquid supply mechanism (10) which has supply ports (13A, 14A) forsupply of the liquid (1) on first and second sides of a projection area(AR1) respectively and which supplies the liquid from the supply ports(13A, 14A), the image of the pattern being projected onto the projectionarea (AR1) by the projection optical system (PL), wherein:

the liquid supply mechanism (10) supplies the liquid from the supplyport (13A) disposed on the first side when the liquid supply mechanism(10) starts the supply of the liquid (1).

According to the seventh aspect of the present invention, the period oftime, which is required to sufficiently fill the space between theprojection optical system and the substrate with the liquid, can beshortened, and the throughput can be improved. Further, the spacebetween the projection optical system and the substrate can be filledwith the liquid more reliably while suppressing the remaining of thebubble.

According to an eighth aspect of the present invention, there isprovided an exposure apparatus which exposes a substrate (P) byprojecting an image of a pattern through a liquid (1) onto thesubstrate, the exposure apparatus comprising:

a projection optical system (PL) which projects the image of the patternonto the substrate (P); and

a liquid supply mechanism (10) which has supply ports (13A, 14A) forsupply of the liquid (1) on first and second sides of a projection area(AR1) respectively and which supplies the liquid from the supply ports(13A, 14A), the image of the pattern being projected onto the projectionarea (AR1) by the projection optical system (PL), wherein:

the liquid supply mechanism (10) supplies the liquid in differentamounts respectively from the supply port (13A) on the first side andthe supply port (14A) on the second side when the liquid supplymechanism (10) starts the supply of the liquid (1).

According to the eighth aspect of the present invention, the period oftime, which is required to sufficiently fill the space between theprojection optical system and the substrate with the liquid, can beshortened, and the throughput can be improved. Further, the spacebetween the projection optical system and the substrate can be filledwith the liquid more reliably while suppressing the remaining of thebubble.

According to a ninth aspect of the present invention, there is providedan exposure method for exposing a substrate (P) by projecting an imageof a pattern through a liquid (1) onto the substrate with a projectionoptical system (PL), the exposure method comprising:

starting supply of the liquid to a projection area (AR1) onto which theimage of the pattern is to be projected, while moving an object (P, PST)arranged on an image plane side of the projection optical system beforeperforming exposure operation; and

exposing the substrate by projecting the image of the pattern onto thesubstrate (P) through the liquid (1) between the projection opticalsystem (PL) and the substrate (P).

According to the ninth aspect of the present invention, the period oftime, which is required to sufficiently fill the optical path spacedisposed on the image plane side of the projection optical system withthe liquid, can be shortened, and the throughput can be improved.Further, the space between the projection optical system and thesubstrate can be filled with the liquid more reliably while suppressingthe remaining of the bubble.

According to a tenth aspect of the present invention, there is provideda method for producing a device, comprising using the exposure apparatus(EX) according to any one of the aspects described above. According tothe present invention, the throughput can be improved, and it ispossible to provide the device having the pattern formed with thesatisfactory pattern accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic arrangement illustrating an embodiment of anexposure apparatus of the present invention.

FIG. 2 shows a plan view illustrating a schematic arrangement of aliquid supply mechanism and a liquid recovery mechanism.

FIG. 3 shows a magnified sectional view illustrating major partsdisposed in the vicinity of a supply port and a recovery port.

FIG. 4 schematically illustrates the behavior of the liquid.

FIG. 5 schematically illustrates the behavior of the liquid.

FIG. 6 schematically illustrates the behavior of the liquid.

FIG. 7 shows shot areas set on a substrate.

FIG. 8 shows a flow chart illustrating exemplary steps of producing asemiconductor device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

An explanation will be made below about an embodiment of the exposureapparatus according to the present invention with reference to thedrawings. However, the present invention is not limited thereto.

FIG. 1 shows a schematic arrangement illustrating an embodiment of theexposure apparatus of the present invention. With reference to FIG. 1,an exposure apparatus EX includes a mask stage MST which supports a maskM, a substrate stage PST which supports a substrate P, an illuminationoptical system IL which illuminates, with an exposure light beam EL, themask M supported by the mask stage MST, a projection optical system PLwhich performs projection exposure for the substrate P supported by thesubstrate stage PST with an image of a pattern of the mask M illuminatedwith the exposure light beam EL, and a control unit CONT whichcollectively controls the overall operation of the exposure apparatusEX.

The exposure apparatus EX of this embodiment is a liquid immersionexposure apparatus to which the liquid immersion method is applied inorder that the exposure wavelength is substantially shortened to improvethe resolution and the depth of focus is substantially widened. Theexposure apparatus EX includes a liquid supply mechanism 10 whichsupplies the liquid 1 onto the substrate P, and a liquid recoverymechanism 20 which recovers the liquid 1 from the substrate P. Theexposure apparatus EX forms a liquid immersion area AR2 on a part of thesubstrate P including a projection area AR1 of the projection opticalsystem PL by the liquid 1 supplied from the liquid supply mechanism 10at least during the period in which the pattern image of the mask M istransferred onto the substrate P. Specifically, the exposure apparatusEX is operated as follows. That is, the space between the surface of thesubstrate P and the optical element 2 disposed at the end portion of theprojection optical system PL is filled with the liquid 1. The patternimage of the mask M is projected onto the substrate P to expose thesubstrate P therewith via the projection optical system PL and theliquid 1 disposed between the projection optical system PL and thesubstrate P.

The embodiment of the present invention will now be explained asexemplified by a case using the scanning type exposure apparatus(so-called scanning stepper) as the exposure apparatus EX in which thesubstrate P is exposed with the pattern formed on the mask M whilesynchronously moving the mask M and the substrate P in mutuallydifferent directions (opposite directions) in the scanning directions.In the following explanation, the Z axis direction is the directionwhich is coincident with the optical axis AX of the projection opticalsystem PL, the X axis direction is the synchronous movement direction(scanning direction) for the mask M and the substrate P in the planeperpendicular to the Z axis direction, and the Y axis direction is thedirection (non-scanning direction) perpendicular to the Z axis directionand the X axis direction. The directions of rotation (inclination) aboutthe X axis, the Y axis, and the Z axis are designated as θX, θY, and θZdirections respectively. The term “substrate” referred to hereinincludes those obtained by coating a semiconductor wafer surface with aphotoresist as a photosensitive material, and the term “mask” includes areticle formed with a device pattern to be subjected to the reductionprojection onto the substrate.

The illumination optical system IL is used so that the mask M, which issupported on the mask stage MST, is illuminated with the exposure lightbeam EL. The illumination optical system IL includes, for example, anexposure light source, an optical integrator which uniformizes theilluminance of the light flux radiated from the exposure light source, acondenser lens which collects the exposure light beam EL supplied fromthe optical integrator, a relay lens system, and a variable fielddiaphragm which sets the illumination area on the mask M illuminatedwith the exposure light beam EL to be slit-shaped. The predeterminedillumination area on the mask M is illuminated with the exposure lightbeam EL having a uniform illuminance distribution by the illuminationoptical system IL. Those usable as the exposure light beam EL radiatedfrom the illumination optical system IL include, for example, emissionlines (g-ray, h-ray, i-ray) in the ultraviolet region radiated, forexample, from a mercury lamp, far ultraviolet light beams (DUV lightbeams) such as the KrF excimer laser beam (wavelength: 248 nm), andvacuum ultraviolet light beams (VUV light beams) such as the ArF excimerlaser beam (wavelength: 193 nm) and the F₂ laser beam (wavelength: 157nm). In this embodiment, the ArF excimer laser beam is used.

The mask stage MST supports the mask M. The mask stage MST istwo-dimensionally movable in the plane perpendicular to the optical axisAX of the projection optical system PL, i.e., in the XY plane, and it isfinely rotatable in the θZ direction. The mask stage MST is driven by amask stage-driving unit MSTD such as a linear motor. The maskstage-driving unit MSTD is controlled by the control unit CONT. Amovement mirror 50 is provided on the mask stage MST. A laserinterferometer 51 is provided at a position opposed to the movementmirror 50. The position in the two-dimensional direction and the angleof rotation of the mask M on the mask stage MST are measured inreal-time by the laser interferometer 51. The result of the measurementis outputted to the control unit CONT. The control unit CONT drives themask stage-driving unit MSTD on the basis of the result of themeasurement obtained by the laser interferometer 51 to thereby positionthe mask M supported on the mask stage MST.

The projection optical system PL projects the pattern on the mask M ontothe substrate P at a predetermined projection magnification β to performthe exposure. The projection optical system PL includes a plurality ofoptical elements including the optical element (lens) 2 provided at theend portion on the side of the substrate P. The optical elements aresupported by a barrel PK. In this embodiment, the projection opticalsystem PL is the reduction system having the projection magnification βwhich is, for example, ¼ or ⅕ . The projection optical system PL may beany one of the 1× magnification system and the magnifying system. Theoptical element 2, which is disposed at the end portion of theprojection optical system PL of this embodiment, is provided detachably(exchangeably) with respect to the barrel PK. The liquid 1 in the liquidimmersion area AR2 makes contact with the optical element 2.

The optical element 2 is formed of fluorite. Fluorite has a highaffinity for water. Therefore, the liquid 1 is successfully allowed tomake tight contact with the substantially entire surface of the liquidcontact surface 2 a of the optical element 2. That is, in thisembodiment, the liquid (water) 1, which has the high affinity for theliquid contact surface 2 a of the optical element 2, is supplied.Therefore, the highly tight contact is effected between the liquid 1 andthe liquid contact surface 2 a of the optical element 2. The opticalpath between the optical element 2 and the substrate P can be reliablyfilled with the liquid 1. The optical element 2 may be formed of quartzhaving a high affinity for water. A water-attracting (lyophilic orliquid-attracting) treatment may be applied to the liquid contactsurface 2 a of the optical element 2 to further enhance the affinity forthe liquid 1.

The substrate stage PST supports the substrate P. The substrate stagePST includes a Z stage 52 which holds the substrate P by the aid of asubstrate holder, an XY stage 53 which supports the Z stage 52, and abase 54 which supports the XY stage 53. The substrate stage PST isdriven by a substrate stage-driving unit PSTD such as a linear motor.The substrate stage-driving unit PSTD is controlled by the control unitCONT. When the Z stage 52 is driven, the substrate P, which is held onthe Z stage 52, is subjected to the control of the position (focusposition) in the Z axis direction and the positions in the θX and θYdirections. When the XY stage 53 is driven, the substrate P is subjectedto the control of the position in the XY directions (position in thedirections substantially parallel to the image plane of the projectionoptical system PL). That is, the Z stage 52 controls the focus positionand the angle of inclination of the substrate P so that the surface ofthe substrate P is adjusted to match the image plane of the projectionoptical system PL in the auto-focus manner and the auto-leveling manner.The XY stage 53 positions the substrate P in the X axis direction andthe Y axis direction. It goes without saying that the Z stage and the XYstage may be provided in an integrated manner.

A movement mirror 55, which is movable together with the substrate stagePST with respect to the projection optical system PL, is provided on thesubstrate stage PST (Z stage 52). A laser interferometer 56 is providedat a position opposed to the movement mirror 55. The angle of rotationand the position in the two-dimensional direction of the substrate P onthe substrate stage PST are measured in real-time by the laserinterferometer 56. The result of the measurement is outputted to thecontrol unit CONT. The control unit CONT drives the substratestage-driving unit PSTD on the basis of the result of the measurement ofthe laser interferometer 56 to thereby position the substrate Psupported on the substrate stage PST.

An auxiliary plate 57 is provided on the substrate stage PST (Z stage52) so that the substrate P is surrounded thereby. The auxiliary plate57 has a flat surface which has approximately the same height as that ofthe surface of the substrate P held by the substrate holder. In thisarrangement, a gap of about 0.1 to 2 mm is provided between theauxiliary plate 57 and the edge of the substrate P. However, the liquid1 scarcely flows into the gap owing to the surface tension of the liquid1. Even when the vicinity of the circumferential edge of the substrate Pis subjected to the exposure, the liquid 1 can be retained under theprojection optical system PL by the aid of the auxiliary plate 57.

The liquid supply mechanism 10 supplies the predetermined liquid 1 ontothe substrate P. The liquid supply mechanism 10 includes a first liquidsupply unit 11 and a second liquid supply unit 12 which are capable ofsupplying the liquid 1, a first supply member 13 which is connected tothe first liquid supply unit 11 through a supply tube 11A having a flowpassage and which has a supply port 13A for supplying, onto thesubstrate P, the liquid 1 fed from the first liquid supply unit 11, anda second supply member 14 which is connected to the second liquid supplyunit 12 through a supply tube 12A having a flow passage and which has asupply port 14A for supplying, onto the substrate P, the liquid 1 fedfrom the second liquid supply unit 12. The first and second supplymembers 13, 14 are arranged closely to the surface of the substrate P,and they are provided at positions which are different from each otherin the surface direction of the substrate P. Specifically, the firstsupply member 13 of the liquid supply mechanism 10 is provided on oneside (−X side) in the scanning direction with respect to the projectionarea AR1, and the second supply member 14 is provided on the other side(+X side).

Each of the first and second liquid supply units 11, 12 includes, forexample, a tank for accommodating the liquid 1, and a pressurizing pump.The first and second liquid supply units 11, 12 supply the liquid 1 fromthe positions over the substrate P through the supply tubes 11A, 12A andthe supply members 13, 14 respectively. The operation of the first andsecond liquid supply units 11, 12 for supplying the liquid is controlledby the control unit CONT. The control unit CONT is capable ofcontrolling the liquid supply amounts per unit time onto the substrate Pby the first and second liquid supply units 11, 12 independentlyrespectively.

In this embodiment, pure water is used as the liquid 1. Those capable ofbeing transmitted through pure water include the ArF excimer laser beamas well as the emission line (g-ray, h-ray, i-ray) in the ultravioletregion radiated, for example, from a mercury lamp and the farultraviolet light beam (DUV light beam) such as the KrF excimer laserbeam (wavelength: 248 nm).

The liquid recovery mechanism 20 recovers the liquid 1 from the surfaceof the substrate P. The liquid recovery mechanism 20 includes a recoverymember 22 which has a recovery port 22A arranged closely to the surfaceof the substrate P, and a liquid recovery unit 21 which is connected tothe recovery member 22 through a recovery tube 21A having a flowpassage. The liquid recovery unit 21 includes, for example, a suckingunit such as a vacuum pump, and a tank for accommodating the recoveredliquid 1, and the like. The liquid recovery unit 21 recovers the liquid1 from the surface of the substrate P via the recovery member 22 and therecovery tube 21A. The operation of the liquid recovery unit 21 forrecovering the liquid is controlled by the control unit CONT. Thecontrol unit CONT is capable of controlling the liquid recovery amountper unit time by the liquid recovery unit 21.

A trap member 30, which is formed with a liquid trap surface 31 having apredetermined length to capture the liquid 1, is arranged outside therecovery member 22 of the liquid recovery mechanism 20.

FIG. 2 shows a plan view illustrating a schematic arrangement of theliquid supply mechanism 10 and the liquid recovery mechanism 20. Asshown in FIG. 2, the projection area AR1 of the projection opticalsystem PL is designed to have a rectangular shape in which the Y axisdirection (non-scanning direction) is the longitudinal direction. Theliquid immersion area AR2, which is filled with the liquid 1, is formedon a part of the substrate P so that the projection area AR1 is coveredthereby. The first supply member 13 of the liquid supply mechanism 10,which is used to form the liquid immersion area AR2 of the projectionarea AR1, is provided on one side (−X side) in the scanning directionwith respect to the projection area AR1, and the second supply member 14is provided on the other side (+X side).

The first and second supply members 13, 14 have internal spaces 13H, 14Hfor allowing the liquid 1 fed from the first and second liquid supplyunits 11, 12 to flow therethrough, and supply ports 13A, 14A forsupplying, onto the substrate P, the liquid 1 having flown through theinternal spaces 13H, 14H respectively. Each of the supply ports 13A, 14Aof the first and second supply members 13, 14 is formed to have asubstantially circular arc-shaped slit form as viewed in the plan view.The size of the supply port 13A, 14A in the Y axis direction is designedto be larger than at least the size of the projection area AR1 in the Yaxis direction. The supply ports 13A, 14A, which are formed to besubstantially circular arc-shaped as viewed in the plan view, arearranged to interpose the projection area AR1 in relation to thescanning direction (X direction). That is, the straight line, whichconnect the center of the projection area AR1 and the respective centralportions of the supply ports 13A, 14A in the Y axis direction, issubstantially parallel to the X axis direction. The liquid supplymechanism 10 is capable of simultaneously supplying the liquid 1 fromthe supply ports 13A, 14A on the both sides of the projection area AR1.

The recovery member 22 of the liquid recovery mechanism 20 is adual-structured annular member having a recovery port 22A which isformed annularly and continuously so that the recovery port 22A isdirected to the surface of the substrate P, and an annular internalspace (internal flow passage) 22H which allows the liquid 1 recoveredthrough the recovery port 22A to flow therethrough. The recovery member22 of the liquid recovery mechanism 20 is arranged to surround theprojection area AR1 and the supply members 13, 14 of the liquid recoverymechanism 10. Partition members 23, which divide the internal space 22Hinto a plurality of spaces (divided spaces) 24 in the circumferentialdirection, are provided at predetermined intervals in the recoverymember 22. The respective divided spaces 24, which are divided by thepartition members 23, make penetration at upper portions. The lower endof the recovery member 22 having the recovery port 22A is disposedclosely to the surface of the substrate P. On the other hand, the upperend is a collected space (manifold) for spatially collecting theplurality of divided spaces 24. One end of the recovery tube 21A isconnected to the manifold, and the other end is connected to the liquidrecovery unit 21. The liquid recovery mechanism 20 recovers the liquid 1from the substrate P by the aid of the recovery port 22A (recoverymember 22) and the recovery tube 21A by driving the liquid recovery unit21. In this embodiment, the recovery port 22A of the liquid recoverymechanism 20 is substantially circular and annular as viewed in the planview, which surrounds the supply ports 13A, 14A and the projection areaAR1. The recovery member 22 is not limited to the circular annularmember, and may be provided by combining, for example, circulararc-shaped members divided for the +X side and the −X side respectively.

FIG. 3 shows a magnified side sectional view illustrating major parts todepict the first and second supply members 13, 14 and the recoverymember 22 arranged closely to the substrate P. As shown in FIG. 3, theinternal flow passages 13H, 14H of the first and second supply members13, 14, respectively, are provided substantially perpendicularly to thesurface of the substrate P. Similarly, the internal flow passage 22H ofthe recovery member 22 of the liquid recovery mechanism 20 is alsoprovided substantially perpendicularly to the surface of the substrateP. The supply positions of the liquid 1 supplied by the first and secondsupply members 13, 14 to the substrate P (positions of installation ofthe supply ports 13A, 14A) are set between the liquid recovery positionof the liquid recovery mechanism 20 (position of installation of therecovery port 22A) and the projection area AR1. In this embodiment, thepositions (heights) in the Z axis direction are set to be identical forthe supply ports 13A, 14A, the recovery port 22A, and the lower endsurface of the projection optical system PL respectively.

In this embodiment, at least the members for allowing the liquid 1 toflow therein, which are included in the respective members forconstructing the liquid supply mechanism 10 and the liquid recoverymechanism 20, are formed of, for example, synthetic resin such aspolytetrafluoroethylene. Accordingly, it is possible to suppress thecontamination of the liquid 1 with any impurity. Alternatively, themembers may be formed of metal such as stainless steel. The flow passagesurface may be coated with a material containing silver. Silver not onlyhas the affinity for the liquid 1, but silver is also excellent in theantimicrobial property. It is possible to suppress the pollution(proliferation of microbes or the like) caused for the liquid 1 and themembers disposed therearound. The member itself, in which the liquid 1flows, may be formed of a material containing silver. When the member,in which the liquid 1 flows, is synthetic resin or the like, it ispossible to adopt such an arrangement that silver (or silver fineparticles) is embedded and arranged on the flow passage surface.

The trap member 30, which is formed with the liquid trap surface 31having predetermined lengths to capture the liquid 1 unsuccessfullyrecovered by the recovery member 22 of the liquid recovery mechanism 20,is provided outside the recovery member 22 of the liquid recoverymechanism 20 in relation to the projection area AR1. The trap member 30is attached to the outer side surface of the recovery member 22. Thetrap surface 31 is the surface (i.e., the lower surface) of the trapmember 30 directed toward the substrate P. The trap surface 31 isinclined with respect to the horizontal plane as shown in FIG. 3.Specifically, the trap surface 31 is inclined to make separation fromthe surface of the substrate P (to be directed upwardly) at outerpositions with respect to the projection area AR1 (liquid immersion areaAR2). The trap member 30 is formed of, for example, metal such asstainless steel.

As shown in FIG. 2, the trap member 30 is an annular member as viewed inthe plan view. The trap member 30 is connected to the outer side surfaceof the recovery member 22 so that the trap member 30 is fitted to therecovery member 22. In this embodiment, the trap member 30 and the trapsurface 31 as the lower surface thereof are substantially elliptical asviewed in the plan view. The length of the trap surface 31 in thescanning direction (X axis direction) is longer than that in thenon-scanning direction (Y axis direction).

A lyophilic or liquid-attracting treatment (water-attracting treatment)is applied to the trap surface 31 to enhance the affinity for the liquid1. In this embodiment, the liquid 1 is water. Therefore, the surfacetreatment, which is in conformity with the affinity for water, isapplied to the trap surface 31. The surface of the substrate P is coatedwith a water-repelling (with a contact angle of about 70 to 80°)photosensitive material (for example, TARF-P6100 produced by TOKYO OHKAKOGYO CO., LTD.) for the ArF excimer laser. The liquid affinity of thetrap surface 31 for the liquid 1 is higher than the liquid affinity ofthe photosensitive material applied to the surface of the substrate Pfor the liquid 1. The surface treatment for the trap surface 31 isperformed depending on the polarity of the liquid 1. In this embodiment,the liquid 1 is water having large polarity. Therefore, as for theliquid-attracting treatment for the trap surface 31, a thin film isformed with a substance such as alcohol having a molecular structurewith large polarity. Accordingly, the liquid-attracting property orhydrophilicity is given to the trap surface 31. As described above, whenwater is used as the liquid 1, it is desirable to adopt such a treatmentthat a substance having the molecular structure with the large polaritysuch as the OH group is arranged on the trap surface 31. In this case,the thin film for the surface treatment is formed of a material which isinsoluble in the liquid 1. The treatment condition of theliquid-attracting treatment is appropriately changed depending on thematerial characteristic of the liquid 1 to be used.

Next, an explanation will be made about a method for exposing thesubstrate P with the pattern image of the mask M by using the exposureapparatus EX described above.

With reference to FIG. 1 again, the exposure apparatus EX of thisembodiment performs the projection exposure for the pattern image of themask M onto the substrate P while moving the mask M and the substrate Pin the X axis direction (scanning direction). During the scanningexposure, a part of the pattern image of the mask M is projected ontothe rectangular projection area AR1 disposed just under the end portionof the projection optical system PL. The mask M is moved at the velocityV in the −X direction (or in the +X direction) with respect to theprojection optical system PL, in synchronization with which thesubstrate P is moved at the velocity β·v(β represents the projectionmagnification) in the +X direction (or in the −X direction) by the aidof the XY stage 53. As shown in a plan view of FIG. 7, a plurality ofshot areas S1 to S12 are set on the substrate P. After the exposure iscompleted for one shot area, the next shot area is moved to the scanningstart position in accordance with the stepping movement of the substrateP. The scanning exposure process is successively performed thereafterfor the respective shot areas while moving the substrate P in thestep-and-scan manner. In this embodiment, the control unit CONT movesthe XY stage 53 while monitoring the output of the laser interferometer56 so that the optical axis AX of the projection optical system PL isadvanced along broken line arrows 58 as shown in FIG. 7 in relation tothe shot areas S1 to S12 on the substrate.

FIG. 3 shows a state brought about immediately after the substrate P isloaded on (imported to) the substrate stage PST. In order to form theliquid immersion area AR2 after loading the substrate P on the substratestage PST, the control unit CONT starts the supply of the liquid 1 bythe liquid supply mechanism 10 while moving the substrate P. In thissituation, the control unit CONT also starts the driving of the liquidrecovery mechanism 20. The control unit CONT starts the movement of thesubstrate P by the aid of the substrate stage PST, and then the controlunit CONT starts the supply of the liquid 1 with only one supply port ofthe supply ports 13A, 14A provided on the both sides of the projectionarea AR1 of the projection optical system PL. In this procedure, thecontrol unit CONT controls the operation for supplying the liquid by thefirst and second liquid supply units 11, 12 of the liquid supplymechanism 10 to supply the liquid 1 from the portion disposed at aposition approaching the projection area AR1 in relation to the scanningdirection.

FIG. 4 schematically shows a state brought about immediately afterstarting the supply of the liquid 1. As shown in FIG. 4, the substrate Pis moved in the +X direction in this embodiment, and the supply of theliquid 1 is started from only the supply port 13A. In this procedure,the timing, at which the supply of the liquid 1 is started from thesupply port 13A, may be any one of those during the acceleratingmovement of the substrate P, and during the movement at a constantvelocity, after the start of the movement of the substrate P. Thecontrol unit CONT effects the supply of the liquid 1 onto the substrateP in a state in which the liquid supply amount per unit time from thesupply port 13A is approximately constant while moving the substrate Pat approximately the constant velocity movement and at a predeterminedspeed. The liquid 1, which is supplied from the supply port 13A arrangedon the −X side with respect to the projection area AR1, i.e., from thesupply port 13A arranged at the rearward position in the direction ofmovement of the substrate, is quickly arranged between the projectionoptical system PL and the substrate P such that the liquid 1 is pulledby the substrate P allowed to move in the +X direction.

FIG. 5 schematically shows a state in which the space between theprojection optical system PL and the substrate P is filled with theliquid 1. As shown in FIG. 5, the liquid 1, which is supplied from thesupply port 13A, is smoothly arranged between the projection opticalsystem PL and the substrate P. In this situation, only the gas (air) isrecovered from the area disposed on the −X side of the recovery port 22Aof the liquid recovery mechanism 20, and the liquid (or the gas and theliquid) is recovered from the area disposed on the +X side.

When the substrate P is moved in the +X direction, then the amount ofthe liquid allowed to move toward the +X side with respect to theprojection area AR2 is increased, and all of the liquid 1 cannot berecovered in some cases in the area disposed on the +X side of therecovery port 22A. However, the liquid 1, which is unsuccessfullyrecovered by the recovery port 22A disposed on the +X side, is capturedby the trap surface 31 of the trap member 30 which is provided on the +Xside from the liquid recovery position (on the outer side with respectto the projection area AR1). Therefore, the liquid 1 is neither allowedto outflow nor scattered, for example, to the surroundings of thesubstrate P. Further, the liquid 1 is not supplied from the supply port14A disposed on the +X side. Therefore, the amount of the liquid allowedto flow to the recovery port 22A on the +X side is reduced. Therefore,it is possible to suppress the occurrence of any inconvenience whichwould be otherwise caused such that the liquid 1 cannot be recovered bythe recovery port 22A and the liquid 1 flows out.

After the liquid immersion area AR2 is formed by the supply of theliquid from one supply port 13A, the control unit CONT starts the supplyof the liquid 1 from the supply ports 13A, 14A disposed on the bothsides. After that, the control unit CONT starts the exposure process forthe respective shot areas S1 to S12 on the substrate P.

In the exposure process, the control unit CONT drives the first andsecond liquid supply units 11, 12 of the liquid supply mechanism 10respectively to simultaneously supply the liquid 1 from the supply ports13A 14A onto the substrate P. The liquid 1, which is supplied from thesupply ports 13A, 14A onto the substrate P, forms the liquid immersionarea AR2 which has a range wider than that of the projection area AR1.

During the exposure process, the control unit CONT controls theoperation of the first and second liquid supply units 11, 12 of theliquid supply mechanism 10 to supply the liquid so that the supplyamount per unit time of the liquid supplied from the positionapproaching the projection area AR1 in relation to the scanningdirection is set to be larger than the supply amount of the liquidsupplied from the position on the oppositeside (position leaving orseparating away from the projection area AR in relation to the scanningdirection). For example, when the exposure process is performed whilemoving the substrate P in the +X direction, the control unit CONT isoperated such that the amount of the liquid supplied from the −X sidewith respect to the projection area AR1 (i.e., from the supply port 13Awhich corresponds to the position approaching the projection area AR1 inrelation to the scanning direction) is larger than the amount of theliquid supplied from the +X side (i.e., from the supply port 14A whichcorresponds to the position leaving the projection area AR1 in relationto the scanning direction). On the other hand, when the exposure processis performed while moving the substrate P in the −X direction, theamount of the liquid supplied from the +X side with respect to theprojection area AR1 is larger than the amount of the liquid suppliedfrom the −X side. The amount of the liquid to be supplied from thesupply port 13A onto the substrate P when substrate P is moving in the+X direction may be set to be approximately identical with the amount ofthe liquid to be supplied from the supply port 14A onto the substrate Pwhen the substrate P is moving in the −X direction. Further, the amountof the liquid to be supplied from the supply port 14A onto the substrateP when substrate P is moving in the +X direction may be set to beapproximately identical with the amount of the liquid to be suppliedfrom the supply port 13A onto the substrate when substrate P is movingin the −X direction.

The control unit CONT drives the liquid recovery unit 21 of the liquidrecovery mechanism 20 to perform the operation to recover the liquidfrom the substrate P concurrent with the operation to supply the liquid1 by the liquid supply mechanism 10. Accordingly, the liquid 1 on thesubstrate P, which flows to the outside of the supply ports 13A, 14Awith respect to the projection area AR1, is recovered from the recoveryport 22A. The liquid 1, which has been recovered from the recovery port22A, passes through the recovery tube 21A, and the liquid 1 is recoveredby the liquid recovery unit 21. The control unit CONT performs theprojection exposure of the pattern image of the mask M onto thesubstrate P via the projection optical system PL and the liquid 1disposed between the projection optical system PL and the substrate Pwhile moving the substrate stage PST for supporting the substrate P inthe X axis direction (scanning direction). During this process, theliquid supply mechanism 10 simultaneously supplies the liquid 1 by theaid of the supply ports 13A, 14A from the both sides of the projectionarea AR1 in relation to the scanning direction. Therefore, the liquidimmersion area AR2 is formed uniformly and satisfactorily. Even when thescanning direction of the substrate P is alternately switched into the+X direction and the −X direction, it is possible to continue the supplyfrom the supply ports 13A, 14A.

When the first shot area S1 on the substrate P is subjected to theexposure, the substrate P is moved in the +X direction. When thesubstrate P is moved in the +X direction, then the amount of the liquidmoved toward the +X side with respect to the projection area AR1 isincreased, and the recovery port 22A, which has the liquid recoveryposition disposed on the +X side, cannot recover all of the liquid 1 insome cases. However; the liquid 1, which is unsuccessfully recovered bythe recovery port 22A on the +X side, is captured by the trap surface 31of the trap member 30 provided on the +X side with respect to the liquidrecovery position. Therefore, the liquid 1 does not cause the scatteringand the outflow, for example, to the surroundings of the substrate P. Inthis embodiment, the trap surface 31 is subjected to theliquid-attracting treatment for the liquid 1, and the trap surface 31has the affinity for the liquid higher than that of the surface of thesubstrate P. Therefore, the liquid 1, which intends to outflow to theoutside of the liquid recovery position of the recovery port 22A, is notpulled toward the substrate P but is pulled toward the trap surface 31.Accordingly, the occurrence of any inconvenience is suppressed, whichwould be otherwise caused, for example, such that the liquid 1 remainson the substrate P.

When the exposure process is completed for the first shot area, thecontrol unit CONT causes the stepping movement of the substrate P inorder that the projection area AR1 of the projection optical system PLis arranged on the second shot area which is different from the firstshot area. Specifically, the control unit CONT causes the steppingmovement in the Y axis direction between the two shot areas S1, S2 onthe substrate P, for example, in order to perform the scanning exposureprocess for the shot area S2 after the completion of the scanningexposure process for the shot area S1. The control unit CONT alsocontinues the operation to supply the liquid onto the substrate P by theliquid supply mechanism 10 during the stepping movement. The exposure isperformed for the shot area S2 while moving the substrate P in the −Xdirection. Subsequently, the exposure process is successively performedfor the plurality of shot areas S3 to S12 respectively.

As explained above, the liquid immersion area AR2 is formed by startingthe supply of the liquid 1 from only one supply port 13A of the supplyports 13A, 14A arranged on the both sides of the projection area AR1,after loading the substrate P on the substrate stage PST. Accordingly,it is possible to quickly form the liquid immersion area AR2 whilesuppressing the formation of any bubble or the like. As schematicallyshown in FIG. 6, it is also conceived that the supply of the liquid 1 isstarted simultaneously from the supply ports 13A, 14A disposed on theboth sides in a state in which the substrate P is allowed to standstill. However, in this case, the following possibility arises. That is,the flows of the liquid, which are supplied from the supply ports 13A,14A disposed on the both sides, make collision or interference with eachother. For example, the central portion AR3, which is included in thearea intended or expected to undergo the formation of the liquidimmersion area, is not filled with the liquid 1, and/or any bubble orthe like is formed. However, when the supply of the liquid 1 is startedfrom only the supply port 13A, it is possible to form the liquidimmersion area AR2 quickly and smoothly.

In the embodiment described above, the movement of the substrate P isstarted before starting the supply of the liquid 1 from the supply port13A onto the substrate P. However, it is also allowable that themovement of the substrate P is started after the elapse of apredetermined period of time after the start of the supply of the liquid1 or substantially simultaneously with the start of the supply or theliquid 1. Also in this procedure, it is possible to form the liquidimmersion area AR2 quickly and smoothly.

When the liquid 1 is supplied from only one of the supply ports 13A, 14Adisposed on the both sides, the liquid 1 may be supplied in a state inwhich the substrate P is allowed to stand still. There is such apossibility that a certain period of time is required until theformation of the liquid immersion area AR2 is completed as compared withthe case in which the liquid 1 is supplied while moving the substrate P.However, the formation of any bubble or the like can be suppressed, andit is possible to suppress the occurrence of the inconvenience whichwould be otherwise caused such that the central portion AR3, which isdisposed in the area between the projection optical system PL and thesubstrate P, is not smoothly filled with the liquid 1, as compared withthe case in which the liquid 1 is supplied simultaneously from thesupply ports 13A, 14A disposed on the both sides in the state in whichthe substrate P is allowed to stand still.

On the other hand, when the liquid 1 is supplied while moving thesubstrate P, it is possible to start the supply of the liquid 1substantially simultaneously from the supply ports 13A, 14A disposed onthe both sides. In this procedure, it is possible to suppress theoccurrence of the inconvenience which would be otherwise caused suchthat the central portion AR3, which is disposed in the area between theprojection optical system PL and the substrate P, is not smoothly filledwith the liquid 1, because the substrate P is moved.

When the liquid 1 is supplied onto the substrate P from the supply ports13A, 14A disposed on the both sides respectively, the supply can bestarted in different amounts from the supply ports 13A, 14A disposed onthe both sides. For example, when the supply of the liquid 1 is startedwhile moving the substrate P in the +X direction as in the embodimentdescribed above, the liquid supply amount per unit time from the supplyport 13A disposed on the −X side with respect to the projection area AR1is made larger than the liquid supply amount per unit time from thesupply port 14A disposed on the +X side. Accordingly, it is possible tosuppress the formation of any bubble in the liquid immersion area AR2while suppressing the occurrence of the inconvenience which would beotherwise caused such that the portion in the vicinity of the centralportion AR3 in the area between the projection optical system PL and thesubstrate P is not filled with the liquid 1. That is, as shown in FIG.5, when the supply port 14A disposed on the +X side does not supply theliquid 1, the internal space 14H of the supply member 14 of the supplyport 14A is in the state of being filled with the gas (air). Therefore,an inconvenience may be possibly caused such that a part of the gasenters into the liquid immersion area AR2 via the supply port 14A.However, when a minute amount of the liquid 1 is also supplied from thesupply port 14A onto the substrate P, and the internal space 14H of thesupply member 14 is filled with the liquid 1, then it is possible toavoid the occurrence of the inconvenience which would be otherwisecaused such that the gas contained in the internal space 14H enters intothe liquid immersion area AR2 when the supply of the liquid 1 is startedfrom the supply port 14A during the operation for forming the liquidimmersion area before the exposure process and/or upon the start of theexposure process.

When the liquid 1 is supplied approximately simultaneously from thesupply ports 13A, 14A disposed on the both sides while moving thesubstrate P, it is preferable that the supply of the liquid 1 is startedwhile moving the substrate P in the X axis direction. However, theliquid immersion area AR2 can be also formed, for example, even when theliquid 1 is supplied while moving the substrate P in the Y axisdirection or in the oblique direction.

When the liquid 1 is supplied while moving the substrate P in the X axisdirection, the supply of the liquid 1 may be started by from anothersupply port provided separately from the supply ports 13A, 14A at anyposition deviated in relation to the scanning direction, for example, inthe ±Y direction or in any oblique direction with respect to theprojection area AR1 without performing the supply of the liquid 1 fromthe supply ports 13A, 14A arranged on the both sides of the projectionarea AR1 in relation to the scanning direction. Alternatively, thesupply may be started by combining the another supply port and thesupply ports 13A, 14A. The supply from the another supply port may bestopped after the formation of the liquid immersion area AR2, and theexposure process may be performed while supplying the liquid 1 from thesupply ports 13A, 14A.

On the other hand, the following procedure is also available. That is,the supply of the liquid 1 is started, while moving the substrate P inparallel to the X axis direction, by using the supply ports 13A, 14Aarranged on the both sides of the projection area AR1 in relation to thescanning direction (X axis direction) when the scanning exposure isperformed for the plurality of shot areas S1 to S12 set on the substrateP as in the embodiment described above. Accordingly, the exposureprocess can be started for the first shot area S1 of the substrate Pimmediately after the liquid immersion area AR2 is formed.

Another supply ports may be provided on the both sides of the projectionarea AR1 in relation to the non-scanning direction (Y axis direction) toform the liquid immersion area by starting the supply of the liquid 1from these supply ports while moving the substrate P in the Y axisdirection. After (or before) stopping the supply of the liquid 1 fromthe another supply ports, the supply of the liquid 1 may be started fromthe supply ports 13A, 14A to perform the exposure process.

The embodiment of the present invention is constructed such that theliquid 1 is supplied from only one supply port 13A during the operationfor forming the liquid immersion area before the exposure process, thesupply of the liquid 1 is started from the both supply ports 13A, 14Aafter forming the liquid immersion area, and then the exposure processis started. However, the following procedure may be also adopted. Thatis, the supply of the liquid 1 is started from only the supply port 13Adisposed on one side during the operation for forming the liquidimmersion area before the exposure process, and the supply of the liquid1 is started from the supply ports 13A, 14A disposed on the both sidesafter the elapse of a predetermined period of time. In other words, theoperation for supplying the liquid is started by using the supply ports13A, 14A disposed on the both sides at an intermediate timing during theoperation for forming the liquid immersion area before the exposureprocess. Accordingly, it is also possible to form the liquid immersionarea AR2 quickly and smoothly.

The direction of movement of the substrate P upon the start of thesupply of the liquid 1 may be determined depending on the direction ofmovement of the substrate P upon the scanning exposure for the firstshot area S1 on the substrate P. For example, when the first shot areaS1 is subjected to the exposure while moving the substrate P in the +Xdirection, the exposure for the first shot area S1 can be startedwithout any unnecessary movement of the substrate stage PST by startingthe supply of the liquid 1 during the movement of the substrate P in the−X direction to be performed immediately therebefore.

It is preferable that the liquid supply amount per unit time from thesupply port 13A (or 14A) during the operation for forming the liquidimmersion area before the exposure process is approximately the same asthe liquid supply amount during the exposure process. If the liquidsupply amount during the operation for forming the liquid immersion areabefore the exposure process is different from the liquid supply amountduring the exposure process, any waiting period of time is requireduntil the supply amount of the liquid is stabilized, for example, whenthe supply amount during the operation for forming the liquid immersionarea is switched into the liquid supply amount during the exposureprocess. However, when the liquid supply amount before the exposureprocess is the same as the liquid supply amount during the exposureprocess, then it is unnecessary to provide any waiting period of time,and it is possible to improve the throughput.

When the liquid 1 is supplied in order to form the liquid immersion areaAR2 before the exposure process, the movement velocity of the substrateP may be either constant or irregular. The movement velocity of thesubstrate stage PST before the exposure process may be either the sameas or different from the movement velocity during the exposure process.During the operation for forming the liquid immersion area before theexposure process, the substrate P may be moved in the predetermineddirection (+X direction) while repeating the movement and the stop ofthe substrate P. Alternatively, the liquid 1 may be supplied whileswinging the substrate P (substrate stage PST) in the XY plane.

During the operation for forming the liquid immersion area before theexposure process, the following procedure can be also adopted. That is,for example, the liquid 1 is supplied from the supply port 13A (or fromboth of the supply ports 13A, 14A) while moving the substrate P in the+X direction, and then the liquid 1 is supplied from the supply port 14A(or from both of the supply ports 13A, 14A) while moving the substrate Pin the −X direction. This operation is repeated a predetermined numberof times.

The supply of the liquid 1 from the liquid supply mechanism 10 may bestarted in a state in which the substrate P is positioned just below theprojection optical system PL. Alternatively, the supply of the liquid 1from the liquid supply mechanism 10 may be started in a state in whichthe flat surface around the substrate P (upper surface of the substratestage PST) is positioned just below the projection optical system PL.

The liquid 1, which is disposed on the image plane side of theprojection optical system PL, may be recovered every time when theexposure is completed for one piece of the substrate. Alternatively, theliquid 1 may be recovered every time when the exposure is completed fora plurality of pieces of the substrates or only when the recovery isrequired, for example, upon the maintenance, on condition that theliquid 1 can be continuously retained on the image plane side of theprojection optical system PL during the exchange of the substrate P aswell. In any case, the procedure as explained in the embodimentdescribed above is carried out when the supply of the liquid is startedfrom the liquid supply mechanism 10 thereafter. Accordingly, it ispossible to quickly form the liquid immersion area containing no bubbleor no air mass (void).

When a sensor or the like, which judges whether or not the liquidimmersion area AR2 is formed, is installed beforehand, the exposure canbe started for the first shot area S1 after confirming the output of thesensor. Alternatively, the exposure may be started for the first shotarea S1 after the elapse of a predetermined waiting period of time afterthe start of the supply of the liquid from the liquid supply mechanism10.

In the embodiment described above, pure water is used as the liquid 1.Pure water is advantageous in that pure water is available in a largeamount with ease, for example, in the semiconductor production factory,and pure water exerts no harmful influence, for example, on the opticalelement (lens) and the photoresist on the substrate P. Further, purewater exerts no harmful influence on the environment, and the content ofimpurity is extremely low. Therefore, it is also expected to obtain thefunction to wash the surface of the substrate P and the surface of theoptical element provided at the end surface of the projection opticalsystem PL.

It is approved that the refractive index n of pure water (water) withrespect to the exposure light beam EL having a wavelength of about 193nm is approximately in an extent of 1.44. When the ArF excimer laserbeam (wavelength: 193 nm) is used as the light source of the exposurelight beam EL, then the wavelength is shortened on the substrate P by1/n, i.e., to about 134 nm, and a high resolution is obtained. Further,the depth of focus is magnified about n times, i.e., about 1.44 times ascompared with the value obtained in the air. Therefore, when it isenough to secure an approximately equivalent depth of focus as comparedwith the case of the use in the air, it is possible to further increasethe numerical aperture of the projection optical system PL. Also in thisviewpoint, the resolution is improved.

In this embodiment, the optical element 2 is attached to the end of theprojection optical system PL. The lens can be used to adjust the opticalcharacteristics of the projection optical system PL, for example, theaberration (for example, spherical aberration and comatic aberration).The optical element to be attached to the end of the projection opticalsystem PL may be an optical plate to be used for adjusting the opticalcharacteristic of the projection optical system PL. Alternatively, theoptical element may be a plane parallel plate through which the exposurelight beam EL is transmissive.

When the pressure, which is generated by the flow of the liquid 1, islarge between the substrate P and the optical element disposed at theend of the projection optical system PL, it is also allowable that theoptical element is tightly fixed so that the optical element is notmoved by the pressure, rather than allowing the optical element to beexchangeable.

The embodiment of the present invention is constructed such that thespace between the projection optical system PL and the surface of thesubstrate P is filled with the liquid 1. However, the followingarrangement may be also adopted. That is, the space may be filled withthe liquid 1 in a state in which a cover glass constructed of a planeparallel plate is attached, for example, to the surface of the substrateP.

The liquid 1 is water in this embodiment. However, the liquid 1 may beany liquid other than water. For example, when the light source of theexposure light beam EL is the F₂ laser, the F₂ laser beam is nottransmitted through water. Therefore, in this case, liquids preferablyusable as the liquid 1 may include, for example, a fluorine-based fluidsuch as fluorine-based oil and perfluoropolyether (PFPE) through whichthe F₂ laser beam is transmissive. Alternatively, other than the above,it is also possible to use, as the liquid 1, liquids (for example, cedaroil) which have the transmittance with respect to the exposure lightbeam EL, which have the refractive index as high as possible, and whichare stable against the photoresist coated on the surface of thesubstrate P and the projection optical system PL. Also in this case, thesurface treatment is performed depending on the polarity of the liquid 1to be used.

The substrate P, which is usable in the respective embodiments describedabove, is not limited to the semiconductor wafer for producing thesemiconductor device. The applicable substrates include, for example,the glass substrate for the display device, the ceramic wafer for thethin film magnetic head, and the master plate (synthetic quartz, siliconwafer) for the mask or the reticle to be used for the exposureapparatus.

As for the exposure apparatus EX, the present invention is alsoapplicable to the scanning type exposure apparatus (scanning stepper)based on the step-and-scan system for performing the scanning exposurefor the pattern of the mask M by synchronously moving the mask M and thesubstrate P as well as the projection exposure apparatus (stepper) basedon the step-and-repeat system for performing the full field exposure forthe pattern of the mask M in a state in which the mask M and thesubstrate P are allowed to stand still, while successively step-movingthe substrate P. The present invention is also applicable to theexposure apparatus based on the step-and-stitch system in which at leasttwo patterns are partially overlaid and transferred on the substrate P.

The present invention is also applicable to a twin-stage type exposureapparatus provided with two stages in which the substrates such as thewafers to be processed are placed separately so that the substrates canbe moved independently in the XY directions. The structure and theexposure operation of the twin-stage type exposure apparatus aredisclosed, for example, in Japanese Patent Application Laid-open Nos.10-163099 and 10-214783 (corresponding to U.S. Pat. Nos. 6,341,007,6,400,441, 6,549,269, and 6,590,634), Published Japanese Translation ofPCT Application No. 2000-505958 (corresponding to U.S. Pat. No.5,969,441), and U.S. Pat. No. 6,208,407, contents of which areincorporated herein by reference within a range of permission of thedomestic laws and ordinances of the state designated or selected in thisinternational application.

As for the type of the exposure apparatus EX, the present invention isnot limited to the exposure apparatus for the semiconductor deviceproduction for exposing the substrate P with the semiconductor devicepattern. The present invention is also widely applicable, for example,to the exposure apparatus for producing the liquid crystal displaydevice or for producing the display as well as the exposure apparatusfor producing, for example, the thin film magnetic head, the imagepickup device (CCD), the reticle, or the mask.

When the linear motor is used for the substrate stage PST and/or themask stage MST, it is allowable to use any one of those of the airfloating type based on the use of the air bearing and those of themagnetic floating type based on the use of the Lorentz's force or thereactance force. Each of the stages PST, MST may be either of the typein which the movement is effected along the guide or of the guidelesstype in which no guide is provided. An example of the use of the linearmotor for the stage is disclosed in U.S. Pat. Nos. 5,623,853 and5,528,118, contents of which are incorporated herein by referencerespectively within a range of permission of the domestic laws andordinances of the state designated or selected in this internationalapplication.

As for the driving mechanism for each of the stages PST, MST, it is alsoallowable to use a plane motor in which a magnet unit provided withtwo-dimensionally arranged magnets and an armature unit provided withtwo-dimensionally arranged coils are opposed to one another, and each ofthe stages PST, MST is driven by the electromagnetic force. In thisarrangement, any one of the magnet unit and the armature unit isconnected to the stage PST, MST, and the other of the magnet unit andthe armature unit is provided on the side of the movable surface of thestage PST, MST.

The reaction force, which is generated in accordance with the movementof the substrate stage PST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,528,118 (Japanese Patent Application Laid-open No. 8-166475), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

The reaction force, which is generated in accordance with the movementof the mask stage MST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,874,820 (Japanese Patent Application Laid-open No. 8-330224), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

The exposure apparatus EX according to the embodiment of the presentinvention is produced by assembling the various subsystems including therespective constitutive elements as defined in claims so that thepredetermined mechanical accuracy, the electric accuracy, and theoptical accuracy are maintained. In order to secure the variousaccuracies, adjustments performed before and after the assemblinginclude the adjustment for achieving the optical accuracy for thevarious optical systems, the adjustment for achieving the mechanicalaccuracy for the various mechanical systems, and the adjustment forachieving the electric accuracy for the various electric systems. Thesteps of assembling the various subsystems into the exposure apparatusinclude, for example, the mechanical connection, the wiring connectionof the electric circuits, and the piping connection of the air pressurecircuits in correlation with the various subsystems. It goes withoutsaying that the steps of assembling the respective individual subsystemsare performed before performing the steps of assembling the varioussubsystems into the exposure apparatus. When the steps of assembling thevarious subsystems into the exposure apparatus are completed, theoverall adjustment is performed to secure the various accuracies as theentire exposure apparatus. It is desirable that the exposure apparatusis produced in a clean room in which, for example, the temperature andthe cleanness are managed.

As shown in FIG. 8, the microdevice such as the semiconductor device isproduced by performing, for example, a step 201 of designing thefunction and the performance of the microdevice, a step 202 ofmanufacturing a mask (reticle) based on the designing step, a step 203of producing a substrate as a base material for the device, a substrateprocessing step 204 of exposing the substrate with a pattern of the maskby using the exposure apparatus EX of the embodiment described above, astep 205 of assembling the device (including a dicing step, a bondingstep, and a packaging step), and an inspection step 206.

According to the present invention, the optical path space on the imageplane side of the projection optical system can be quickly filled withthe liquid while suppressing the formation of any bubble or the like.Therefore, the exposure process can be performed at the high throughputwithout causing any deterioration of the image of the pattern.

1. An exposure method for exposing a substrate by projecting an image ofa pattern through a liquid onto the substrate, the exposure apparatuscomprising: starting supply of the liquid from one side of a projectionarea to the projection area onto which the image of the pattern is to beprojected, before performing exposure operation; supplying the liquidfrom both sides of the projection area during the exposure operation;and exposing the substrate by projecting the image of the pattern ontothe substrate through the supplied liquid, wherein the liquid issupplied in different amounts from both sides of the projection areaduring the exposure operation.
 2. An exposure apparatus which exposes asubstrate by projecting an image of a pattern through a liquid onto thesubstrate, the exposure apparatus comprising: a projection opticalsystem which projects the image of the pattern onto the substrate; and aliquid supply mechanism which has supply ports for supply of the liquidon both sides of a projection area respectively and which supplies theliquid from the supply ports, the image of the pattern being projectedonto the projection area by the projection optical system, wherein: theliquid supply mechanism supplies the liquid in different amountsrespectively from the supply ports disposed on both sides when theliquid supply mechanism starts the supply of the liquid.
 3. The exposureapparatus according to claim 2, wherein each of the plurality of shotareas on the substrate is exposed while moving the substrate in apredetermined scanning direction, and the supply ports are arranged onboth sides of the projection area in relation to the scanning direction.4. The exposure apparatus according to claim 2, wherein the supply ofthe liquid by the liquid supply mechanism is started while moving thesubstrate.
 5. The exposure apparatus according to claim 2, furthercomprising a control unit which controls the liquid supply mechanism sothat the liquid is supplied in different amounts from the supply portsof the liquid supply mechanism disposed on both sides of the projectionarea.
 6. The exposure apparatus according to claim 2, further comprisinga substrate stage which is movable while holding the substrate, whereinthe control unit controls movement of the substrate stage.
 7. Anexposure method for exposing a substrate by projecting an image of apattern through a liquid onto the substrate, the exposure methodcomprising: starting supply the liquid in different amounts respectivelyfrom both sides of a projection area onto which the image of the patternis to be projected, before performing exposure operation; and exposingthe substrate by projecting the image of the pattern onto the substratethrough the supplied liquid.
 8. The exposure method according to claim7, further comprising: moving the substrate in a predetermined scanningdirection during the exposure; and starting the supply of the liquid indifferent amounts from both sides of the projection area in relation tothe scanning direction.
 9. The exposure method according to claim 7,further comprising moving the substrate in a predetermined directionwhen the supply of the liquid is started.
 10. An exposure apparatuswhich exposes a substrate by projecting an image of a pattern through aliquid onto the substrate, the exposure apparatus comprising: aprojection optical system which projects the image of the pattern ontothe substrate; and a liquid supply mechanism which has supply ports forsupply of the liquid on first and second sides of a projection arearespectively and which supplies the liquid from the supply ports, theimage of the pattern being projected onto the projection area by theprojection optical system, wherein: the liquid supply mechanism suppliesthe liquid in different amounts respectively from the supply port on thefirst side and the supply port on the second side when the liquid supplymechanism starts the supply of the liquid.
 11. The exposure apparatusaccording to claim 10, wherein the first and second sides include bothsides of the projection area.
 12. An exposure method for exposing asubstrate by projecting an image of a pattern through a liquid onto thesubstrate with a projection optical system, the exposure methodcomprising: starting supply of the liquid to a projection area ontowhich the image of the pattern is to be projected, while moving anobject arranged on an image plane side of the projection optical systembefore performing exposure operation; and exposing the substrate byprojecting the image of the pattern onto the substrate through theliquid between the projection optical system and the substrate; whereinthe supply of the liquid is started from both of first and second sidesof the projection area in different amounts.
 13. A method for producinga device, comprising using the exposure apparatus as defined in claim 2.14. A method for producing a device, comprising using the exposureapparatus as defined in claim 10.